EarthTalk®

Written by the Editors of E/The Environmental Magazine

March 01, 2010

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Dear EarthTalk: When the plug-in Prius is released, how much electricity will it

"According to the blog Futurewheels.com, electric cars and plug-in hybrids (those that have been converted by owners) currently average about two cents per mile to recharge, while gasoline-only cars average about 10 cents per mile to refuel. Pictured: a Toyota Prius Plug-in Hybrid demonstration program vehicle at the 2010 Washington, DC Auto Show."Credit image to "Mario Roberto Duran Ortiz, courtesy Flickr."

use? Will my electric bill double if my Prius is plugged in each night? Or will the increase be minimal? Also, will all this recharging put a strain on the existing electricity grid? -- G.C. Marx, Colorado Springs, CO

It is difficult to pinpoint the answer to this question right now since Toyota has not yet released its much anticipated plug-in hybrid, but most analysts believe the increase in your electric bill from overnight charging will be minimal. According to the blog Futurewheels.com, electric cars and plug-in hybrids (those that have been converted by owners) currently average about two cents per mile to recharge (electric rates vary greatly by region), while gasoline-only cars average about 10 cents per mile to refuel.

Plug In America, a California based network of electric vehicle and (self-converted) plug-in hybrid owners, estimates the cost to charge a typical plug-in hybrid overnight to be less than a dollar. So while your electric bill might go up $30/month due to recharging, your gas bill will decrease by somewhere between 80 and 100 percent depending on your driving habits and what you were driving beforehand.

Of course, it’s important to keep in mind that regular hybrids cost between $2,000 and $10,000 more than their gas-only counterparts, and that plug-in hybrids will likely cost even more due to their larger, better batteries and other more advanced technologies. It would take years and years of gasoline-free driving to make up the sticker-price difference between a plug-in hybrid and an equivalent-sized gasoline-fueled car. So while plug-in hybrids will help the environment, they’re not so much about saving money—unless you drive thousands of miles a week, in which case you’ll recoup your costs in fuel savings in a few years.

As to strain on the existing electricity grid, most experts agree that plug-in hybrids and all-electric vehicles, even in the unlikely event that all of us switched over to them eventually, wouldn’t compromise the ability of utilities to provide power, given that they are already scaled up to handle peak loads during heat waves when everyone runs energy-hogging air conditioning.

Furthermore, most of us would charge our cars overnight—typically a slow period for utilities otherwise and during which they could generate much more power if customers wanted it. A 2007 study by the U.S. Department of Energy’s Pacific Northwest National Laboratory found that off-peak electricity capacity could fuel the daily commutes of nearly three-quarters of all cars, light trucks, SUVs and vans on American roads today if they were plug-in hybrids. Plug In America adds that many utilities are upgrading local electricity distribution systems to accommodate plug-in hybrids and electric vehicles “just as they do when residents add more air conditioners and TVs.”

So if you’re interested in taking the plug-in hybrid plunge when the cars become available, don’t worry about increased electric bills, as overall you’ll be saving gobs of cash at the pump. And given the popularity of the current hybrids on the road, enough of us might go for the plug-in versions so as to reduce the cost disparity with traditional cars—meaning we could “save green” in more ways than one.

snow removal taking place on roads everywhere in the wake of all the recent storms? -- Benjamin P Sander, via e-mail

The act of removing pure white snow seems innocuous enough, but it is actually fraught with negative environmental side effects. One major concern is the snow’s salt content, as most locales use sodium chloride (rock salt) to de-ice roads. But this salt can make nearby freshwater ecosystems uninhabitable for plant and wildlife species, and can affect the quality and taste of local drinking water supplies.

Besides salt, removed snow contains accumulated amounts of antifreeze, engine oil, rubber and metal deposits from tire wear, and heaps of plastic litter, cigarette butts and other waste which is also poisonous to local ecosystems no matter where it ends up.

Researchers in Toronto, Ontario have found that at least one local snow dump has been wreaking havoc in the nearby Don River. “Road salt adversely affects sensitive species when it exceeds 200 milligrams per liter of water,” reports journalist Michael Lehan. “Almost half of the test results taken between 2002 and 2005 in the river exceeded that, and the highest concentration recorded was almost 4,000 milligrams per liter.” The result, he says, is that the river can barely support life. “Only six pollution resistant fish species…can be found in the river.” Across town in the city’s west end, the Humber River—which doesn’t have a snow dump to contend with—supports some 30 species of fish.

Many regions are working on ways to green their snow removal processes. In Maryland, for example, road crews are pre-treating major roadways with brine, a saltwater solution that helps prevent snow and ice from sticking and thus reduces the amount of salt needed after a storm. The state is also experimenting with a beet juice and brine mix with the hope that it will stick to roads better and prevent snow and ice build-up. Massachusetts pre-treats roads with magnesium chloride to help prevent incoming snow and ice from sticking, and also uses a sodium chloride and calcium chloride mix on icy roads in environmentally sensitive areas and when the temperature gets too low (below 20 degrees Fahrenheit) for rock salt to be effective. According to the U.S. Environmental Protection Agency (EPA), using de-icers properly can cut down on the amount applied overall and improve road conditions.

Regardless of how much and what de-icers a given locale chooses to use, where the resulting removed snow ends up is the most important environmental consideration. In New Hampshire, another state that’s no stranger to snow, state officials require the placement of a silt fence between snow dumps and any nearby waterways, and have mandated that snow storage areas be at least 400 feet from municipal wells.

Of course, those who complain about the environmental effects of snow removal should consider the root cause of the problems: The concentrated hazards in snow dumps—from rock salt to motor oil—are mostly a direct result of our society’s reliance on the private automobile. While asking your local and state government to green up their snow removal operations is one way to help, another is to choose mass transit or carpool whenever you can, and to convince as many friends as you can to do likewise.